The proposed investigation will concern itself with the structure and function of an intercellular junction, the gap junction, isolated from mammalian heart and liver. The isolated junctions will be studied by electronmicroscopy, x-ray diffraction, SDS-polyacrylamide gel electrophoresis and chromatography, amino acid analysis and sequence, and thin-layer chromatography. Intact junctions in the tissues will be studied in novel preparations which permit the splitting of the junctions with hypertonic disaccharides. Ciliary dyskinesia will be examined in hypertonic sucrose- and cystic fibrosis factor-treated epithelia, in the hope of understanding the mechanisms of metachronal waves and the mechanism of ciliary uncoupling by the factor. Membranes and junctions from other tissues of cystic fibrotic individuals will be examined as well with thin-sectioning and freeze-fracturing. Bibliographic references: Goodenough, D.A. 1975 Methods for the isolation and structural characterization of hepatocyte gap junctions. In Methods in Membrane Biology, Vol. III, E.D. Korn, ed., Plenum Press, N.U. pp. 5l-80. Goodenough, D.A. 1975 The structure of cell membranes involved in intercellular communication. Am. J. Clin. Pathol. 63: 636-645.